For the patient with a successful organ transplant, the musculoskeletal complications of non-specific bone pain and osteonecrosis all too frequently arise within the first several years after transplantation and are debilitating just as the patient is enjoying a new lease on life. The long term objectives of this proposal are to study 3 issues central to the musculoskeletal problems encountered by transplant patients. (1) Nonspecific bone pain (NSBP) is a newly recognized entity which is poorly understood and is secondary to immunosuppression. It may be related to early stage osteonecrosis. This proposal will prospectively study the natural history, improve the diagnostic criteria and test calcium channel blockers in the treatment of NSBP using a double blind, randomized study as well as explore a potential relationship to osteonecrosis. (2) Osteonecrosis of the femoral head (ONFH) is a dreaded complication of immunosuppression as it is crippling and there is no treatment which can reliably salvage the hip joint. A reversible stage of osteonecrosis has recently been described. This proposal will use MRI to prospectively study whether or not a reversible stage exists and the prognostic factors which may predict which patients will develop progressive collapse f the femoral head. (3) At present, surgical procedures to preserve the hip joint are unreliable in their success. This proposal will use functional and clinical outcomes measurement to study a new procedure, core decompression with methylmethacrylate cement packing, designed to prevent or forestall the development of end-stage arthritis in patients with either pre- femoral head collapse ONFH (single blind, randomized, prospective study), or post-femoral head collapse ONFH (single blind, randomized, prospective study), or post-femoral head collapse ONFH (prospective study).